function check_private_groups_topic_ids($post_ids)
{
    //Init the Array which will hold our list of allowed posts
    $allowed_posts = array();
    //Loop through all the posts
    foreach ($post_ids as $post_id) {
        //Get the Forum ID based on Post Type Topic
        $topic = bbp_get_topic_post_type();
        $forum_id = private_groups_get_forum_id_from_post_id($post_id, $topic);
        //Check if User has permissions to view this Post ID
        //by calling the function that checks if the user can view this forum, and hence this post
        if (private_groups_can_user_view_post_id($forum_id)) {
            //User can view this post - add it to the allowed array
            array_push($allowed_posts, $post_id);
        }
    }
    //Return the list
    return $allowed_posts;
}
function pg_get_author_link()
{
    $user_id2 = wp_get_current_user()->ID;
    // Parse arguments against default values
    $r = bbp_parse_args($args, array('post_id' => $post_id, 'link_title' => '', 'type' => 'both', 'size' => 14), 'pg_get_author_link');
    //confirmed topic
    if (bbp_is_topic($post_id)) {
        $topic = bbp_get_topic_post_type();
        $forum_id_check = private_groups_get_forum_id_from_post_id($post_id, $topic);
        //now we can check if the user can view this
        if (!private_groups_can_user_view_post($user_id2, $forum_id_check)) {
            return;
        }
        return bbp_get_topic_author_link($r);
        // Confirmed reply
    } elseif (bbp_is_reply($post_id)) {
        $reply = bbp_get_reply_post_type();
        $forum_id_check = private_groups_get_forum_id_from_post_id($post_id, $reply);
        //now we can check if the user can view this
        if (!private_groups_can_user_view_post($user_id2, $forum_id_check)) {
            return;
        }
        return bbp_get_reply_author_link($r);
    }
    // Neither a reply nor a topic, so could be a revision
    //if it isn't a topic or reply, not sure so better to just not display the author in this case
    //could be revised to look up the post_parent of this post and then churn that round the code above if required return ;
    return;
}